Method of dyeing sponges



FIFSZSO? izo UKITH bill]- UNITED STATES PATENT OFFICE METHOD OF DYEING SPONGES Milton Cohn, New York, N. Y.

No Drawing. Application November 6, 1934, Serial No. 751,707

4 Claims.

The invention relates to a method of dyeing natural bath sponge to a fast color and to the resulting product.

The expression .natural bath sponge used herein is to define the animal formation phylum porifera, and specifically Silicispongice, taken from the sea and having various commercial designations such as sheepswool (,S'pongz'a equiua) velvet, reef, yellow, silk, mandrukas, loofah,grass and glove sponge (Spongza tubulifem), in distinction from rubber and certain other vegetable and'synthetic products now on the market and erroneously designated as sponge.

The primary object of the invention is to provide a dyed or colored sponge to match the colors of bath rooms, toilet accessories and the like, now in general use and 'at the same time to maintain, or even better the soft, velvety, fluffy appearance characterizing forms of bleached natural sponge now on the market.

It has been suggested, as disclosed in the English patent to Asher 14,866 of July 19, 1905, that sponges of some unidentified type could be dyed when treated first with a metallic mordant at some unidentified temperature and then dyed in an alizarine bath at temperatures of to degrees centigrade (158-176" F.). The primary objection to sponge dyed'in accordance with the suggestions in the Asher patent is that the colors are not fast and the resulting so-called sponge bleeds when Wetted with warm water. Further, mordants of the type in general use in 1905, such as the basic aluminium sulphates suggested, in order to be effective must necessarily be heated at temperatures approaching the boiling point even if the boiling point is not actually reached. Sponges dyed by the method disclosed in this English patent do shrivel up despite the claim in the patent that shrivelling is avoided when the alizarinelakes are maintained at temperatures not exceeding the '70 to 80 degrees centigrade. However, a more serious objection than simply that the sponge becomes shrivelled and cannot retain the color of the lake in which it was dyed, is that it is otherwise deleteriously affected in its physical characteristics as for instance it loses to a large extent its elasticity, or spring, or life. Any temperature as high as 70-80 C. appears to destroy or at least partially close the inhalant pores, the canals, the apoyles, and the oscules, and thus interferes with the Water flow through the sponge passageways. It is a commercial requirement of sponges that they shall have a smooth, sometimes referred to as a pleasant touch, when wet; that they have capacity to absorb large volumes of water and that this water be discharged by manual action and without too much resistance to the crushing of the Wet sponge during washing operations.

It has been found experimentally that no commercial form of sponge could stand a temperature greater than that which can be comfortable to a persons hand, herein arbitrarily fixed at F. (49 0.), Without suffering objectionable changes in physical construction. The 120 F. limit herein mentioned is not to be regarded as critical because somefine silky grades of natural sponge, such as the Mediterranean sponges, are injured at temperatures even less than 120 F., and some of the tougher sponges such as the West Indian species can be subjected to temperatures as high as F. without serious effeet, but in general 120? F. is about as high a temperature as can be safely employed in the treating of natural sponge and at the same time avoid any noticeable shrinking, or loss of "life, or water pumping capacity. It has also been found that prolonged heating, 'even at 120 F. affects the sponge structure in undesirable ways. On the other hand dyeing operations ingeneral are most successfully performed and in fact'must be performed with the dye bath abovethe prevailing atmospheric temperature and within known limits, the higher the temperature, the better is the resulting dyeing. 7

Accordingly the present invention features a method of producing dyed sponge by means of which brilliant, fast, uniform, and otherwise pleasing, color effects may be produced, while at the same time retaining all of the physical characteristics such as velvety touch, elasticity or life, capacity to absorb and discharge water, a light, fiuify porous appearance, and'the other attributes which are associated with high grade bleached sponges now in general use. The present disclosure features what may be called a cold, or more accurately, an atmospheric temperature process, maintained during the several bleaching and washing steps, while limiting the dyeing step or steps to that higher temperature just sufficient to insure a dyeing which will resist subsequent washings, and in no case sufficiently high to deleteriously affect the sponge structure and in those cases where it is advisable to raise the temperature of any bath above the prevailing atmospheric temperature tomaintain the same as much below 120 F. as possible and to continue the treatment at the high temperaf ture periods for as short a period of time as can be economically practiced. r

M le- UM" white appearance results after which it is washed Briefly, the method consists in subjecting the sponge to a cold bleaching process, known generally as a permanganate of potash bleach and then, preferably without drying the bleached sponge, and while still wet,;to subject it to the dyeing action of those aniline colors of the diazo class which can be used to eifect a fast dye on the sponge at 120 F. without deleterious action. 7 Apparently better results areobtained if the process is carried out as a continuous operation without intermittent drying, and better results areobtained where the dyeing steps hereinafter more specifically defined promptly follow the preliminary or bleaching steps. Better colors are produced on nascently bleached sponge, particularly sponge which has been bleached by the permanganate of potassium method, than isthe case where the bleached sponge is permitted to remain for several days before being subjected to the dyeing operation herein featured. One method which has been developed to give a satisfactory dyeing to all the classes of sponge above identified, is specifically recited hereinafter but it will'be understood, of course, that variations in the reagents and in the proportions of the reagents hereinafter recited can be made, as will be understood by the experienced dyer, and in general it will be understood that coarser grades 'of sponge need not be so carefully treated as the more expensive, finer silky grades.

In the following specific definition of a preferred method, it will be understood that in enumerating the percentage of the reagents forming the several solutions such percentages will be by weight of the amount of sponge treated; thatall' of the baths are highly diluted, the amount of water used being between 40-60 parts water to one part reagent solution and that, except in the color precipitating Step G, the temperature of all the baths will beat atmospheric temperature, preferably at about 100 F. or atleast materially less than 120 F., and-that in the color precipitatin'g step the bath will be at a temperature sufl'icientlyhigh to produce dyeings which will withstand subsequent washing of the sponge but at no time will'this color precipitating step, nor in fact any other stepfbe permitted to rise above 120 F., to any material extent.

The natural sponge is submerged into and carefully and gently stirred in the baths to insure the, penetration of'thesolution material to all parts of the'sponge exterior and interior and to do this in such way so as to avoid anymechanical breake ing of the sponge fibres or otherwise disarranging the natural relation of the structural parts.

A. Preliminary washing The sponge is'wetted in warm water at about 100 F.-, adding if desired a small amount of alkali or soap. The washed sponge is rinsed in a second warm water wash particularly if an alkali or soap has been used in the bath.

B. Bleaching 7 step .The washed sponge is then subjected to a bleaching step in a bath consisting of permanganate ofpotash A to 5%, in whichit is immersed for 15' minutes, removed and washed.

C. Reducing step clean.

D. Repetition If necessary, Steps B and C are repeated with some types of sponge, and this is particularly true of sponge known as mandrukas or silk sponge. Where the sponge is to be dyed certain light delicate shades such as violets and greens, even a third repetition of Steps B and C may be desirable to produce the necessary white bleach.

E. Stain removing step Usually the presence of oxide and iron and. other iron compounds and stains would affect the desired final color tone and it is herein suggested that in this event the bleached sponge be subjected to a stain removing step in a bath consisting of oxalic acid 1% for a period of 1 to 2 hours, or of sulphuric acid 12% for a period of twelve hours, and in either case until all stain has disappeared, after which the sponge is well washed to rid it of the acid.

F. Preliminary coloring step A color bath is then prepared by dissolving any desired aniline color of the diazo class, such, for instance, as diazo fast violet, B. L. for violet or diazo' brilliant green, 3 G for green, in suificient hot water to produce a complete solution of the dye using from to 2% of color depending on the depth of shade required. Sufficient cold water, about forty parts water to each one part of sponge, is added to form a dye bath to float the sponge and initially this bath is at a temperature not materially greater than F. 'The sponge is carefully turned in this cold bath for about five minutes and some color will begin to form on the sponge.

G. Color precipitating step There isthen added to the color bath a quantity of twenty percent sodium chloride solution equal to 10% of the weight of the sponge, as in the case of the violet above indicated, and at the same time the temperature of the color bath is raised to approximately F. and maintained for about ten minutes to constitute a color precipitating step. The amount of salt added has a pronounced influence on the fast--. ness ultimately of the color to Washing of the dyed sponge. In the case of dyeing the green shade above indicated it is necessary to add up to fifty pounds of salt to one hundred pounds of sponge to obtain proper exhaustion. of the bath.

TQThis is a.critical step in the operation and care must be exercised to obtain satisfactory results. The salt should not be added all" at one time. It is suggested that one half of the salt be added during and towards the end of the live minutes stirring while the bath is cold. At this time care shouldbe exercised in exposing different parts of the sponge to the bath material to-insure that all parts of the sponge obtains an which the salt is fed to the bath; if the tint is,

slow' in forming, the rate of salt feeding'is speeded up, and if the tint is formingfso fast as to be unevenly distributed the rate of salt feed- Termites CHEit-ilCAL Monti- GAll SN 0? TEXTELES & FIBERS,

ing is slowed up. With a little experience the skilled dyer can soon determine how fast the color should be formed on the different types of sponge under treatment and what percentage of salt operates best to obtain the maximum exhaustion of the bath which, of course, is an economic desideratum. It-is well also to agitate the bath as the salt is being added to insure a uniform distribution of the salt particles throughout the mass of the bath. With some rugged types of sponge this 120 heating step may be' maintained for a longer period, say thirty minutes, but any prolonged heat treatment should be avoided otherwise the sponge will shrink and lose its life or elasticity. The dyed sponge is then removed from the warm dye bath and well washed.

H. Diazotieing step The dyed and washed sponge is then subjected for a period of about fifteen minutes to a developing step in a cold bath consisting of any one of the commercial diazotizing developers such as are usually employed with diazo colors, such for instance as Trade name Chemical name Developer A Beta naphthol-sodium salt Developer Z Phenyl-methyl-pyrazolonc J. Alkali bath step Preferably there is added to this developing bath an alkali, such as carbonate of soda or caustic soda; The amount of developer and a1- kali in this bath should be equal to the amount of diazo color employed in the preparation of the color bath (Step F). This alkali bath insures the removal of any color not permanently united to the sponge fibre and thus tends to make the color fast.

K. soapy wash step The sponge is then preferably given a soap Wash with any commercial form of soap to defeat any bleeding of the color from the sponge when in subsequent use. In any event the finished sponge is given a thorough rinsing; is permitted to air dry and is then ready for the market. While the sponge may be artificially dried it is preferable to let them dry naturally and slowly and in any event not to subject them to a drying temperature above'say F.

Sponge dyed in practically any of the usual colors and tones can be produced, even delicate blues, reds and the like. Yet the sponge will distinguish in no objectional way from high grade sponge when bleached, but not dyed; that is, dyeing by the method herein disclosed apparently has no deleterious effects. The sponge retains its former capacities to absorb and discharge water, and has the same velvety touch. It has been found moreover, that the sponge so dyed has greater resistance to tearing. action, and has a smoother, more velvety touch than a portion of the same sponge not subjected to dyeing according to the present invention. Another and unexpected discovery resulted in prac- 2,o5e,1c6 3 ticing' this method; 'it was found that a cheap,

low grade and coarse sponge, such, for instance, as the sponge identified in-the trade as grass sponge, becomes softer, more velvety to the touch and more closely resembling. a higher grade than it was originally. It is thus possible not only to dye the sponge to any required color but it is possible to so treat cheap grades of sponge to make of them a new manufactured product which can compete in every way with the higher grade, more expensive types of sponges.

Despite the fact that concerns selling sponges have for a long time warned the purchasing public that when using sponge it should not be subjected to boiling or even to water too hot for the users hands, as high heats ruin sponge, and this is, of course, especially true in the more delicate types, users become careless in this matter. In the case of dyed sponge should it be subjected to high temperatures in hot Water there is present at least some possibility that the dye material will tend to bleed out of the sponge with resulting discoloration of the wash water. In an effort to minimize any such possibility with the sponges when treated as herein outlined, they are subjected as above noted (Step J) to atreatment with an alkali, such as carbonate of soda, in the final developing step. This completion of thedyeing in analkali bath insures the removal or substantial removal of any color not permanently united tothe sponge fibre. No. pretense is made herein that some traces of bleeding will not occur under severe high temperature conditions, but it is a fact that the alkali bath tends to, and in most cases actually does, prevent loss of color or discoloration of the sponge when in subsequent use.

It has been found that bleached sponge dyes much more readily than when unbleached and requires about one-half as much color in the case of the bleached than in the caseofthe unbleached sponge. The bleaching of the sponge apparently .doubles its color absorbing qualities. Bleaching, particularly with the permanganate method above recited gives the sponge aseptic properties and the developers used in Step I act additionally as preservatives to prevent bacteria and mold growth. The accumulative effect of these antiseptics is to provide a sponge which is not only dyed but also a sponge which is surgically cleaned during its manufacture and which thereafter tends to resist souring. In use the sponge treated as herein indicated can be cleaned simply by washing in luke-warm soapy water.

While there has been shown, described and pointed out in the annexed claims, certain novel features of the invention, it will be understood that various omissions, substitutions and changes in the method of practicing the invention in the proportions of reagents used in the several baths, and in the operation of the method may be made by those skilled in the art without departing from the spirit of the invention.

I claim;

1. In the art of dyeing natural sponge to a substantially fast color, the method which consists in practicing a continuous operation without intermediate drying after the initial wetting of the sponge and While maintaining the temperature not materially higher than the prevailing atmospheric temperature, except during the dyeing step hereinafter recited, and at no time subjecting the sponge to any deleterious temperature above F., said operation consisting in subjecting the sponge in succession to a bleach ingioperation until the desired whiteness of color is attained,,introducing the sponge into a dyeing bath of anilinecolor of the diazo class, raising the temperature of the dyeing bath'to a'temperature greater than'atmospheric temperature and sufficiently high to produce a dyeing which will withstand washing, but not materially exceeding 120 F., while'progressively adding a solution of sodium chloride'initially to the cold bath and continuing on'into the warmdye bath,

continuing the dyeing step at such warm tem- 'perature until the desired depth of color is attained, then subjecting thedyed sponge to subsequent steps of the method, at'temperatures below said 120 F., said subsequent steps consisting in washing the dyed sponge, subjecting the washed sponge to a .diazotizing bath, developing the 'diazotized' sponge in a bath of a diazo developer, subjecting the developed sponge to a wash-rinsing andfinally air dryingthe'dyed sponge. V, v I 1 e 2. In the art of dyeing sponge to'a substan- V tially fast color, the method which consists in entering the sponge in a cold dyeing bathcontaining a water solution of an anilinecolor of the diazo class, in the proportion of'ab'out one half to two parts color to one hundred parts of sponge Withlthe wateriin the proportion of about forty to sixty parts water to one part sponge, turning the sponge in said bath for about five minutes,while progressively adding initially to the color-bath and continuing oninto the warm bath, a quantity of sodium chloride in twenty percent solution and equal to about ten percent by weight of the sponge, raising the temperature of the bath to about 120? F; and maintain ing said temperature for about ten minutes, removing the sponge from the 'warm'dyeing bath, and subjecting the same to the action of 'a diazojtizing bath containing three partso f nitrite of soda and six parts of sulphuric acid to one hun-' dred parts of sponge for about fifteen minutes and. at atmospheric temperature removing the sponge from the diazotizing bath and subjecting the same to the action of a'developing bath at atmospheric "temperature and containing a diazo developer and carbonate of soda together equal in Weight to the amount of 'color used in the dyeing bath and finally washing and drying the dyed sponge. V V a 3. A method of dyeing natural sponge to a substantially fast color, which involves subjecting the sponge to a dye bathwhile maintaining the temperature of said bath at a higher temperature than the prevailing atmospheric temperature but one not materially above 120-130 degrees Fahrenheit, said bath containing an aniline color of the diazo class, and then diazot-izing such color, then Washing the sponge, then' developing such color, then washing the sponge,

and then drying the same, the temperature be-' ing reduced to not materially higher than the prevailing atmospheric temperature during such diaZotizing and during all the specified'steps sub sequent to such diazotizing. V V

4. Armethod of dyeing natural ,sponge'to a substantially fast color, which involves subjecting the sponge to a bleaching agent and then to afreducing agent when the sponge is to be dyed'a light or' pastel shade while maintaining the temperature of such agents not materially higher than the prevailing atmospheric tempera-- ture; thereafter subjecting the sponge to a'color bath including an'aniline color of the diazo class whilemaintaining said bath at a higher temperature than that first-mentioned but one considerably below boiling; and thereafter diazotizing such color, and developing such diazotized color in a bath'of a diazo developer, the temperature being reduced to said first-mentioned temperature during such diazotizing and during such developing.

.- MILTON COHN. 

